RESEARCHERS have developed lie detector tests to help police prosecute criminals for the first time in the UK.

Detectives in Merseyside and Cheshire have been asked to test the lie detection equipment to interrogate suspects.

Liverpool University is talking to the forces about real interview tests of a new system that looks for clues from involuntary gestures.

If the tests go ahead, it will be the first time police in the UK have used lie detection technology.

Liverpool psychology professor Ian Donald, one of the researchers involved, said a great deal of interest had been shown in the device called Silent Talker.

The lie detector uses a video camera linked to an artificial intelligence system that spots small tell-tale move-ments people make unconsciously when they lie. Professor Donald said: "We are talking to very senior people but it is very informal at this stage.

"We are also going to contact the Association of Chief Police Officers and our aim is to trial this in real interviews."

The system would only be used in interviews with the consent of suspects and their lawyers. A change in the law would be needed for the results to be admissible in court.

Silent Talker is said to have a 90pc success rate in detecting deceitful answers from a range of responses.

The conventional polygraph, regularly featured in police investigations in the United States, is claimed by

some to have no more than a 60pc to 70pc success rate.

Dr Janet Rothwell, psychology researcher at Manchester Metropolitan University, who spent five years developing the lie detector, added: "The artificial intelligence system watches for micro-gestures, blushing and head and shoulder movement.

"At a basic level, it is trained to identify an object, such as an eye. The next level is to understand if that object is being deformed, for example an eye changing shape."

The Police Information and Technology Organisation, which oversees law enforcement and biometrics research, said it was monitoring the project.

Spokesmen for Merseyside Police and the Cheshire Constabulary said they were unable to say if and when the scheme would go-ahead.

Mark Littlewood, campaigns director for the human rights organisation Liberty, said: "The full consent of the suspect should be required. We are sceptical of its reliability and believe its more widespread use would be a serious erosion of the right to silence."